Generally, in-line mechanisms involve the concept of a first rotating member effecting a reciprocating or oscillating movement upon a second output member. In-line mechanisms currently exist in various forms, such as the slope slot mechanism, the eccentric mechanism, and the rocked bearing mechanism. Each of these mechanisms involves a pair of shafts wherein each of the pair of shafts (a drive shaft and an output shaft) is set parallel to the other. In each type of in-line mechanism, the drive shaft rotates imparting a reciprocating motion to the output shaft via mating components on each shaft which impart force vectors on each other.
For example, the sloped-slot mechanism involves a drive shaft having a rotating component with sloped groove thereon for receiving a protrusion fixed on a second output shaft. As the drive shaft rotates, the protrusion rides along the sloped-slot causing the output shaft to reciprocate. On the other hand, the eccentric mechanism involves a pair of bevel gears mounted on shafts having axes perpendicular to each other, the first gear rotating on a drive shaft axis which rotates the second gear. The second gear has a shaft eccentrically mounted to the output shaft, thereby reciprocally moving the output shaft. Finally, in the rocked bearing mechanism, the drive shaft rotates within a raked bearing which has an end mounted to the output shaft. When the drive shaft rotates, it causes the raked bearing end to swing like a pendulum, thereby causing the output shaft to move in a reciprocating fashion.
While the above described in-line mechanisms allow the output shaft to move in a reciprocating motion with respect to the rotating drive shaft, none of them permit the output shaft to be easily rotated without a special device. Moreover, none of the above in-line mechanisms are capable of having multiple output shafts surrounding the drive shaft.
Consequently, a need has developed for an in-line assembly having an output shaft that can rotate, as well as reciprocate, without a special mechanism. Further, the in-line assembly should be capable of accommodating multiple out-put shafts around or about the input shaft. This in-line assembly should also be fairly inexpensive to manufacture compared to other types of in-line mechanisms.